1. Field of the Invention
The present invention relates to a plant cultivator for research purposes and control system therefor employed in experiments to discover the optimum cultivation environment for plants.
2. Description of the Related Art
Conventionally, in greenhouses or vinyl plastic hot-houses, as a method of promoting plant growth, the method is known of providing a device for illumination with light rays using a fluorescent lamp and/or high-pressure sodium lamp.
Fluorescent lamps and high-pressure sodium lamps emit large quantities of light of wavelengths other than the wavelengths that are effective for plant photosynthesis and it is not possible to intensify exclusively light of the wavelengths that are effective for plant photosynthesis.
Consequently, in order to promote plant growth, it is necessary to use a large number of fluorescent lamps or sodium lamps and to control the illumination time; power consumption of these is high and their life is short and means for controlling the rise in greenhouse temperature produced by the heat generated thereby is necessary. For reasons such as this, with conventional systems, installation costs and running costs are considerable. Furthermore, fluorescent lamps are difficult to control since their illuminance drops at low temperature.
Furthermore, there is the inconvenience that when intense light is generated by fluorescent lamps or high pressure sodium lamps, there is strong emission of light of wavelengths other than wavelengths that are effective for cultivation, the effect of which is to produce bacterial pustules on the plants.
In view of the circumstances described above, the problem that the present invention aims to solve consists in the provision of a plant cultivator and control system therefor capable of being controlled to maintain an optimum environment using as illumination device a light source that chiefly emits light of wavelengths that are effective for plant cultivation without generation of heat or non-useful light, which is capable of coping with high-frequency flashing control, which is considered beneficial in promoting plant photosynthesis and yet which is of high durability. It is intended for use as a plant cultivator for experimental studies such as variety improvement or new variety development for businesses such as cultivating plants of high scarcity value or high-class garden plants or for cultivation of seedlings of high-class vegetables and studies aimed at tissue cultivation and, which is of particular concern, finding optimum growth conditions of plants.
In order to solve the above problem, first of all, a cultivator is formed with a cabinet body that is provided with an opening/closing door in a suitable face thereof and is provided with an illumination window on its upper face or a suitable side face, its inner faces, with the exception of this illumination window, being covered by a thermally insulating wall. In addition, the cabinet comprises at least some of a growth detection sensor that detects how the plants are growing, cultivation environment monitoring means that monitors the cultivation environment, comprising at least one of the temperature, humidity and carbon dioxide gas concentration in the vicinity of the plants (within the cabinet) and cultivation environment generating means that generates said cultivation environment and comprises cultivation environment control means that controls said cultivation environment generating means in accordance with information from said cultivation environment monitoring means at a suitable location within the cabinet or outside the cabinet.
In this specification, xe2x80x9ccarbon dioxide gasxe2x80x9d means carbon dioxide gas supplied with the object of promoting plant photosynthesis and the xe2x80x9cgrowth detection sensorxe2x80x9d is a general term for sensors or a monitoring camera that detect for example changes of weight and/or changes of biopotential that change in accordance with the growth of a plant.
Also, on the upper face or a suitable side face of the cabinet body, an LED illuminating element is arranged so as to face the illuminating window and LED control means is provided that controls the LED illuminating element, in the vicinity of the LED illuminating element or on a suitable side face of the cabinet.
An LED indicates a light-emitting diode. An LED illumination element means an illumination element formed by assembling in a suitable ratio LEDs of a plurality of types that generate light of optimum wavelength in accordance with the types and growth stage of the plants, a large number of these being arranged on a member such as a panel. Even more specifically, it is constituted by a large number of LEDs of one or more types chosen from red, blue, green, white, infra-red or ultraviolet LEDs in a suitable ratio on a board.
Conveniently a large number of types of illumination elements are provided and the construction is such that these illumination elements can be replaced in accordance with the types and state of growth of the plants.
A light amount sensor may be provided within the cabinet and the LED control means may control the amount of light emitted from the LED illuminating element with reference to the amount of light within the cabinet obtained by the light amount sensor.
A plant cultivator comprising a construction as described above may be constituted by forming the illuminating window of two transparent glass sheets or synthetic resin sheets provided with an intervening space, or of glass or synthetic resin integrally formed provided with an intervening space.
The opening/closing door may be constituted of a double-door structure comprising an inner door and outer door, the inner door being formed of glass sheet or synthetic resin sheet and the inside face of the outer door being constituted as a reflecting surface.
Also, in order to ensure that light emitted from the LED illuminating element effectively strikes the plants, being reflected so that it cannot escape to the outside, and to cut off light rays from outside, the inside of the cabinet body with the exception of the illuminating window is made as a reflective surface, for example a white reflective sheet being stuck on to this reflective surface or this reflective surface being coated with a white reflective paint or constituted of white resin. In this way, light is more effectively reflected.
The cultivation environment monitoring means may comprise a temperature sensor; the cultivation environment generating means may comprise temperature generating means that performs heating or cooling of the interior of the cabinet; and the cultivation environment control means may control heating or cooling by the temperature generating means in accordance with the temperature within the cabinet measured by the temperature sensor.
The cultivation environment monitoring means may comprise a carbon dioxide gas sensor; the cultivation environment generating means may comprise carbon dioxide gas supply means that supplies carbon dioxide gas from a carbon dioxide gas supply port provided in the cabinet; and the cultivation environment control means may control the rate of supply of carbon dioxide gas by the carbon dioxide gas supply means in accordance with the carbon dioxide gas concentration found by the carbon dioxide gas sensor.
The cultivation environment monitoring means may comprise a humidity sensor; the cultivation environment generating means may comprise humidity generating means that humidifies or dehumidifies the interior of the cabinet; and the cultivation environment control means may control the humidification or dehumidification by the humidity generating means in accordance with the humidity within the cabinet found by the humidity sensor.
The temperature generating means may comprise a heater and the heater may be incorporated in the thermally insulating wall of the cabinet body. Heating may be performed using a known panel heater or sheathed heater.
The temperature generating means may comprise cooling means which may be arranged to cool the interior of the cabinet by incorporating suitable cooling means such as electronic cooling means employing a cooling medium circulating pipe or Peltier element in the thermally insulating wall of the cabinet body.
The temperature generating means may comprise a Peltier element and may perform temperature control by cooling or heating the interior of the cabinet by changing the direction of passage of current to this Peltier element.
The humidity generating means may comprise a fin cooled by a Peltier element and dehumidifying means constituted by a drain that drains water formed as dew on this fin to outside the cabinet body, thereby achieving dehumidification of the interior of the cabinet.
The humidity generating means may effect humidification by supplying into the interior of the cabinet a mist from a mist supply port provided in the cabinet.
In this specification xe2x80x9cmistxe2x80x9d indicates a mist of water vapor supplied with the object of supplementing supply of moisture to the plant and maintenance of humidity within the cabinet.
Furthermore, preferably, in order to disperse the supplied carbon dioxide gas or carbon dioxide gas and mist uniformly by baffling within the cabinet, the interior of the cabinet body is partitioned using a partition member into a cultivation zone and a supply zone linked with the growth zone and comprising means for stirring the air in the interior and the carbon dioxide gas supply port or carbon dioxide gas supply port and mist supply port are constructed so as to open within the supply zone. The stirring means is not restricted solely to effecting stirring by directing the tip of the supply port in the direction of the interior of the partitioned zone so that the supplied gas is made to collide with the partition member but could beneficially include the provision of a fan in the partitioned zone.
Also, according to the present invention, in a system that controls said plant cultivator by means of a computer connected therewith through a computer network, said computer comprises cultivation environment control data storage means that stores cultivation environment control data for controlling at least one of the carbon dioxide gas concentration, amount of light, temperature and humidity within said cabinet body and cultivator control means that controls sending of data to said LED control means and said cultivation environment control means provided in said plant cultivator in accordance with said cultivation environment control data. In this way, a plurality of plant cultivators connected to a network can be subjected to centralized management and automatic control by a single computer.
Said cultivator control means may be arranged to control said plant cultivator by comparing the cultivation environment detection data detected by said light amount sensor, said temperature sensor and, if necessary, said growth detection sensor and said humidity sensor provided in said plant cultivator with said cultivation environment control data, such as to coincide with said cultivation environment control data.
Also, said cultivation environment control data may be stored in spreadsheet form. In this way, data based on the size and/or coloration of the leaves of the plant whose cultivation environmental conditions are being measured, the thickness of the stem, the height, the size and/or coloration of the flowers and at the size and/or coloration of the fruits or the like can be obtained and cultivation conditions suited to the plant can easily be found by creating new cultivation environment control data in accordance with these and cultivating the plant in accordance therewith.
For the computer network for sending data for controlling said plant cultivator, said computer may employ an access control system of the CSMA/CD (Carrier Sense Multiple Access with Collision Detection) system. Said computer and said plant cultivator may therefore be connected using a network cable such as 10BASE2, 10BASE-T or 100BASE-TX.